Comprehensive analysis of pulsed plasma nitriding preconditions on the fatigue behavior of AISI 304 austenitic stainless steel
来源期刊：International Journal of Minerals Metallurgy and Materials2021年第4期
论文作者：Okan Unal Erfan Maleki Remzi Varol
文章页码：657 - 664
摘 要：This study aims to draw an exact boundary for microstructural and mechanical behaviors in terms of pulsed plasma nitriding conditions.The pulsed plasma nitriding treatment was applied to AISI 304 austenitic stainless steel at different temperatures and durations.Results reveal that nitriding depth increased as process temperature and duration increase.The nitriding depth remarkably increased at 475℃ for 8 h and at 550℃ for 4 h.An austenite structure was transformed into a metastable nitrogen-oversaturated body-centered tetragonal expanded austenite（S-phase） during low-temperature plasma nitriding.The S-phase was converted to CrN precipitation at 475℃ for 8 h and at 550℃ for 4 h.Surface hardness and fatigue limit increased through plasma nitriding regardless of process conditions.The best surface hardness and fatigue limit were obtained at 550℃ for 4 h because of the occurrence of CrN precipitation.
Okan Unal1,2，Erfan Maleki3，Remzi Varol4
1. Mechanical Engineering Department, Karabuk University2. Modern Surface Engineering Laboratory(MSELAB), Karabuk University3. Mechanical Engineering Department, Sharif University of Technology-International Campus4. Mechanical Engineering Department, Suleyman Demirel University
摘 要：This study aims to draw an exact boundary for microstructural and mechanical behaviors in terms of pulsed plasma nitriding conditions.The pulsed plasma nitriding treatment was applied to AISI 304 austenitic stainless steel at different temperatures and durations.Results reveal that nitriding depth increased as process temperature and duration increase.The nitriding depth remarkably increased at 475℃ for 8 h and at 550℃ for 4 h.An austenite structure was transformed into a metastable nitrogen-oversaturated body-centered tetragonal expanded austenite（S-phase） during low-temperature plasma nitriding.The S-phase was converted to CrN precipitation at 475℃ for 8 h and at 550℃ for 4 h.Surface hardness and fatigue limit increased through plasma nitriding regardless of process conditions.The best surface hardness and fatigue limit were obtained at 550℃ for 4 h because of the occurrence of CrN precipitation.
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